1. Field of the Invention
The present invention relates to a method of and an apparatus for winding a film, a method of and an apparatus for supplying a film roll core, and a method of and an apparatus for inspecting the appearance of a film roll, which are applied to a film rewinder or a film cutter to wind a film around a roll core.
2. Description of the Related Art
Generally, film rewinders for automatically winding a film around a core or film cutters for cutting a wider film into a narrower film and automatically winding the narrower film around a core employ an arrangement for cutting an elongate film upstream of a film winding station and thereafter feeding the cut film length to the film winding station. For details, reference should be made to Japanese laid-open patent publication No. 10-25043, for example.
According to the above process, the leading end of the cut film is in a free state and is not controlled. Therefore, the film tends to undulate and it is difficult to align an edge of the film at a constant position with an end of a roll core. For example, rolls of photosensitive material such as print paper have a film edge whose shape is highly important for film quality. If a film edge projects axially outwardly from an end of the roll core, then the projecting film edge tends to be damaged while the film is packaged or delivered.
Various proposals have been made to wind a film around a core highly accurately with simple and inexpensive arrangements. For example, Japanese patent publication No. 7-53547 and Japanese laid-open patent publication No. 10-53360 disclose apparatus in which a product with a wound film is discharged using a vertically movable product receiver, then a new core is supplied, and the film is cut while the film is being nipped by the supplied core and a touch roller.
According to the above proposed structures, while the product is being lowered after it has been unchucked, the film is free of any tension. Therefore, if the film passes through a displaced position, then an edge of the film projects from an end of the roll core.
The above film rewinders and film cutters have an automatic core supply device for automatically supplying a core to a circumferential edge of the film winding station and an automatic film winding device for rotating the roll core supplied from the automatic core supply device to automatically wind the film around the roll core. However, since the automatic core supply device and the automatic film winding device have their operating ranges partly interfering with each other, it is difficult to shorten the period of time after the winding of the film has been completed until a film starts being wound around a new core. This is because after the automatic core supply device has place a core in the film winding station, the automatic core supply device is sufficiently retracted from the film winding station, and then the film starts being wound around the roll core. As a result, the entire process of winding the film around the roll core cannot be speeded up, and the apparatus is complex in structure, resulting in a considerably high cost of equipment.
As disclosed in Japanese laid-open patent publication No. 5-17058, there is known a process of surrounding a new core with an endless belt in a retracted position, moving the endless belt to a winding position after the winding of a web material has been completed in the winding position, and rotating the roll core to wind a new web material therearound.
Since it is difficult to supply the roll core accurately to the winding position with the endless belt only, a member is used to fix the roll core in position. The member needs to be moved back and force by a cylinder, and a time loss is caused to retract the member with the cylinder. In addition, because of the core fixing member used, the endless belt cannot be positioned closely around the roll core fully across its axis, making it difficult to wind the film highly precisely around the roll core.
Rolled film products have end faces whose shapes are important for product quality. For example, rolled film products suffer appearance defects if a rolled film product has a concave conical end face as shown in FIG. 50 of the accompanying drawings, if a rolled film product has a convex conical end face as shown in FIG. 51 of the accompanying drawings, if a rolled film product has a film layer projecting an end face thereof as shown in FIG. 52 of the accompanying drawings, or if a rolled film product has an end face displaced wholly or partly as shown in FIG. 53 of the accompanying drawings. These appearance defects are responsible for damage to the end faces of the products while they are being packaged or delivered. Accordingly, it is necessary to inspect rolled film products for their end face configuration.
It has been customary to visually or tactually inspect rolled film products for their end face configuration. Other processes of inspecting products other than films for their appearance are disclosed in Japanese laid-open patent publications Nos. 6-24649 (first conventional process), 7-304567 (second conventional process), and 9-58930 (third conventional process).
According to the first conventional process, a parallel slit light beam emitted by an illuminating device comprising a light source and a slit is applied from a side of a spinning package to an edge thereof. The irradiated area is imaged by a CCD camera, and the image is processed to effect pattern matching for comparison with a normal package configuration.
According to the second conventional process, a strip-shaped beam of light emitted from a laser oscillator and dispersed by a cylindrical lens is applied to an edge of a yarn package. A yarn filament is raised from the package edge under electrostatic induction, and an image of the raised yarn filament captured by a CCD camera is converted into a binary image. The boundary between non-irradiated and irradiated areas of the binary image, near the non-irradiated area, is scanned by a line sensor, and compared with a threshold value having a predetermined signal width.
According to the third conventional process, laser displacement meters are vertically disposed respectively against face and back end faces of a yarn bobbin. Based on output signals from the laser displacement meters, distances up to the face and back end faces of the yarn bobbin are measured, and surface irregularities of the face and back end faces of the yarn bobbin are measured for automatically determining contour defects of the yarn bobbin.
Since the conventional processes of inspecting rolled film products for their appearance have been manually performed visually or tactually, the rolled film products cannot be evaluated objectively. Evaluation standards tend to vary from lot to lot, personnel expenses that are required are liable to be high, and the period of time required for the inspection is likely to be long, resulting in a poor productivity.
The first through third conventional processes described above are not aimed at the inspection of rolled film products. If these conventional processes are applied to the inspection of rolled film products, then inasmuch they employ commercially available laser displacement meters and light sources, inspected rolled film products may be exposed to undesirable light.
It is a general object of the present invention to provide a method of and an apparatus for winding a film highly accurately and efficiently around a core with a simple process and arrangement.
A primary object of the present invention is to provide a method of and an apparatus for supplying a film roll core to allow a film to be wound quickly and highly accurately around the film roll core, through a simple arrangement.
Another principal object of the present invention is to provide a method of and an apparatus for inspecting the appearance of a film roll accurately within a short period of time without affecting the quality of the film for effectively increasing the production efficiency.
The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which preferred embodiments of the present invention are shown by way of illustrative example.